Tank capacity: 17.6litres. Checked. (BTW:$24)

[marc]

Tank capacity: 17.6litres. Checked.

My tank got completely empty yesterday.

Went to the gas station and I paid for 17.6 litres of fuel.

BTW: it costed me $24 in Spain, Europe.

[RedShift]

What year is your bike?

I've never measured what my tank holds, but the most I've ever put in it was 3.9 gallons (14.7 litres) and that was running on Reserve for 16 kilometers.  I am probably one of those that also can't account for the full 20 litres.

[marc]

It's a '91.

If I refill gas just after switching to RES, I can drop in it 10.5 litres.
So, RES holds 6.5 litres.

But my experience so far is that switching to RES makes my bike lose
lots of power. (In fact, so does the PRI position, this is the reason
why I always drive in the PRI position).

I'm having the fuel starvation problem.